1. Field of the Invention
This invention is directed to a method of inflating tires after the tires have been removed from the curing press, more specifically from 4 to 7 minutes after the tires have been removed from the curing press.
2. Description of the Prior Art
The advent of the nylon tire cord ushered in a new era of tire building technology. Tires made with the new cord were of lighter weight and higher strength than the previous cotton or rayon cord tires. With the new era of high strength cord tires, however, came a new set of problems.
One of the problems was that the nylon cord would stretch while the tire was in service and the rubber did not. This phenomenon resulted in cracks in the rubber, particularly in the grooves of the tire tread during normal service. To remedy this problem, nylon cords having an elastic memory were pre-stressed at a temperature above its heat shrink termperature, cooled below its heat shrink temperature in its stressed state and then used in tire building. This resulted in reduced subsequent stretching of the nylon cord.
Another problem which occurred was that shrinkage of the nylon cord caused distortion of the tire when a hot nylon tire was removed from the mold.
Developments designed to reduce the groove cracking and heat distortion problems included method and apparatus for inflating tires immediately after curing. The prior art, in this era is exemplified by the disclosures of U.S. Pat. Nos. 3,002,228 Salem, et al. (1961); 3,008,180 Woodhall (1961); 3,039,839 Waters, et al. (1961); 2,978,741 Soderquist (1961); and 3,487,507 Turk (1970).